Hinged ramps for platform lifts, which ramps act as barriers or stops to prevent objects from sliding or rolling off the lifts are well known as disclosed in the following three patents:
______________________________________ Rohrs et al 4,124,130 Nov. 7, 1978 Cl. 214/75R Deacon 3,913,759 Oct. 21, 1975 Cl. 214/77R Pearson 4,140,230 Feb. 20, 1979 Cl. 214/77R ______________________________________
There also exists many hinged ramps on platforms with separately hinged barriers or stop plates, particularly those employed on garage vehicle lifts at the end of the channel tracks for the wheels of the vehicle, as disclosed in the following patents:
______________________________________ Hollister 1,946,320 Feb. 6, 1934 Cl. 254/89 Cunneen 2,098,376 Nov. 9, 1937 Cl. 254/89 Ratliff 4,095,704 June 20, 1978 Cl. 214/77P Bristol 1,952,906 Mar. 27, 1934 Cl. 254/89 Hott er al 1,955,586 Apr. 17, 1934 Cl. 254/89 Estel, Jr. 2,569,982 Oct. 2, 1951 Cl. 254/89 Lill 3,252,544 May 24, 1966 Cl. 187/8.52 Bacher 1,938,446 Dec. 5, 1933 C1. 254/89 Clapp 1,966,975 July 17, 1934 Cl. 254/89 Cunneen 1,936,107 Nov. 21, 1933 C1. 254/89 Cochin 1,943,003 Jan. 9, 1934 Cl. 254/89 Tear 2,052,118 Aug. 25, 1936 Cl. 254/89 ______________________________________
These above patents also disclose ground-engaging levers, links, end latches, most of which are quite complicated and contain many moving parts which easily wear, become clogged with dirt, and become jammed and inoperative.